1. Field of the Invention
The present invention relates to a device for performing leak detection at a plurality of test sites.
2. Description of the Prior Art
For leak detection, use is made of a tracer gas, particularly helium, argon or another inert gas, which will pass through a possibly existing leak and be detected on the opposite side. For detecting the tracer gas, there is normally used a mass spectrometer. Since mass spectrometers are very complex and expensive, also other approaches have been developed for detection of a tracer gas. One such approach consists in using a gas-tight measuring cell which is closed by a membrane that is selectively permeable to the tracer gas. In the interior of the measuring cell, a total pressure is generated which corresponds to the partial pressure of the tracer gas outside the measuring cell. By measurement of the total pressure in the measuring cell, the presence and the concentration of the tracer gas can be determined.
Detection of the gas is also possible by absorption spectroscopy. By excitation, tracer gas existing in the measuring cell can be brought to a higher energetic level which is referred to as a metastable state. Metastable gas atoms have a characteristic absorption spectrum and thus are optically detectable by spectroscopy. In spectroscopy, it is required to modulate a laser beam passing through the metastable gas, and to evaluate the signals of the respective radiation receiver. The apparatus involved therein are very complex. In cases where a plurality of test sites exist, the respective technical investment required will be multiplied accordingly.
It is an object of the invention to provide a device for performing leak detection at a plurality of test sites, said device comprising a host unit which is to be used for all of the measurement sites and which can be situated remote from the measuring sites.